Midget gearbox

[stuffedpike20]

I just got what I assume is a midget gearbox. There is wiring for a reversing light, and no release bearing fork fitted.

Apart from fitting a release fork, and bearing, will it fit straight into a 1098 minor? Is there anything that makes it better than a standard minor ribbed gearbox?

Thanks
John

[philthehill]

What is the number stamped on the first motion shaft?
The number will determine what Midget it is from.
Other than a difference in gear ratios and the fact the 1275cc Midget box has the reverse light switch there is little difference.
It will fit straight into a 1098cc Minor when the appropriate clutch fork and release bearing is fitted.

[stuffedpike20]

Thanks Phil. I will have a look tomorrow.

What difference do the gear ratios make? I have a 3.9 diff fitted....will it cope?

Thanks
John

[philthehill]

The gear ratios of the 1275cc Midget are slightly higher for 3rd, 2nd and 1st. Top is 1 to 1 what ever BMC gearbox is fitted. That does not make them any stronger. I found that out the hard way as on a road test of a 1275cc Midget the gearbox broke and had to limp back to the garage. Will it cope - slightly better than a 948cc & 1098cc gearbox. I had a 1275cc SC/CR gearbox in my Minor but it would not cope with the power and I had to upgrade the gearbox to a full Quaife Clubman SC/CR box and it has held together ever since.
Below - full Quaife CR/SC gearbox with alloy casing, alloy top cover and quick shift gear lever. The bell housing is from CS Autoclassics and purchased way back.

Quaife box 2.jpg (1.13 MiB) Viewed 3488 times

[stuffedpike20]

That is a thing of beauty!

[stuffedpike20]

What is the number stamped on the first motion shaft?
The number will determine what Midget it is from.
Other than a difference in gear ratios and the fact the 1275cc Midget box has the reverse light switch there is little difference.
It will fit straight into a 1098cc Minor when the appropriate clutch fork and release bearing is fitted.

I am not sure if this is the right number....stamped on the front bearing cover. 3DDC122G118 .

There is a little tag fitted under a nut on the inspection plate which reads.... RMJ1109E45123 .

The gearbox is painted with flakey silver paint. I don't know if this means it was a silver seal? I don't know the difference between silver seal and gold seal.

Thanks.

[stuffedpike20]

Stop press!
It's all gone wrong!

I cleaned up the outside with lots of parafin. I decided to see how much oil was in it. Oil was very low and looked like used engine oil.
Unfortunately, when I cleaned the crud out of the dimple in the drain plug....I also cleaned out a ball bearing and broken spring. GUTTED.

There is no way back from here....is there?

[les]

My approach would be to identify the ball bearing, by size, and the spring wire thickness. An explosive view of the internal components needed to assist with this. This said, I wouldn’t be happy until I stripped the box. Sorry for your discovery

[stuffedpike20]

Thanks Les.

Ball bearing is about 4 or 5 mm dia. Spring a bit like a wide biro spring.

I'm not good at gearboxes....good job it was relatively cheap.

[les]

4 - 5 mm seems too small to be from one of the gearbox bearings. Maybe from a plunger, the spring giving tension to the ball. Of course, there is a slim possibility that the bits were there prior to a previous rebuild, the drain plug being replaced without inspection. Sorry I’m afraid it’s all guesswork.

[stuffedpike20]

Thanks Les.

I did a little google, and I think the 22G118 number means that the box fits Austin Healey, Sprite, and Midget 1275, so possibly quite sought after even if it needs mending. I might be able to get some of my money back.

The box was advertised as 'working gearbox from a working car', and it probably was. Years ago I had a minor pickup that crunched one time when I changed from first to second on a hil start. The box still worked but was a bit sloppy going from first to second from then on. Months later I changed the oil in the box, and a ball bearing and crushed spring came out with the oil....just like on the midget box.

The main casing of the midget box is painted with what looks like silver hammerite, but the remote is a different colour. I asked my neighbour what the colour is (I am colourblind), and he told me it is 'goldy green'. If it was gold, it might have been from a goldseal box. If it was green....maybe just painted with engine paint.

[philthehill]

Sorry to disappoint you but that 22G118 front cover was also fitted to a 1098cc Minor.
Look on the input shaft and there will be a number stamped on it. What is the number? As I said above that number will confirm what the gearbox was originally fitted to.
The number stamped on a 1275cc Midget gearbox input shaft is 22G229 and if it is that number you have struck lucky.

[stuffedpike20]

Sorry to disappoint you but that 22G118 front cover was also fitted to a 1098cc Minor.
Look on the input shaft and there will be a number stamped on it. What is the number? As I said above that number will confirm what the gearbox was originally fitted to.
The number stamped on a 1275cc Midget gearbox input shaft is 22G229 and if it is that number you have struck lucky.

Sorry Phil, I am not sure what you mean. If the input shaft is the shaft with the splines for the clutch plate....I have had a look and there aren't any numbers on it.

[les]

Yes that’s the shaft, the number can be quite faint to make out.

[philthehill]

I can assure you that the number is there even if faint. The first motion shaft I have in front of me has the number 22G172 (which identifies it as being previously fitted to a MG Midget 1098cc Mk 2) stamped radially around the shaft about halfway between the rear of the splines and the machined surface for the return scroll. I have had to clean the shaft with a bit of fine emery to bring the number to view.

[stuffedpike20]

Thanks. I will have a look when it gets light!

[stuffedpike20]

I just had a look, and yes,there is a number.

It is 22G229 . So a desirable gearbox.....but broken inside.

If I did not have bad luck, I would have no luck at all.
Not sure what to do with it now. Any suggestions?

Thanks Les and Phil.

[philthehill]

Glad you found the number and it is the right number.
Personally I would strip the gearbox and see what is wrong.
Other than that put it up for sale as used and faulty.
As it is the better of the 'A' Series gearboxes there will be someone out there who wants a 1275cc Midget gearbox and is prepared to rebuild it.
Good luck
Phil

[stuffedpike20]

Thanks Phil.

[stuffedpike20]

I have listed the gearbox for sale on here.

Thanks
John.
......NOW SOLD.....